Fuchin is one of the key techniques in Yagami Ryu for managing the movement of a bound person’s body.
Its literal translation is “up and down,” like the tide. In essence, it refers to a force that comes and goes.
Fuchin According to Yagami Ren
Let’s start by exploring the technique through a video by Yagami Ren, where he attempts to explain it.
Personal opinion: I think Yagami Ren struggles to explain Fuchin effectively, especially to a Western audience. He tries to simplify it with an exercise that ends up being unclear and doesn’t make much sense.
But let’s take a look at the video first.
Although Yagami Ren periodically changes the definition, spelling, and explanation of his techniques—especially when he’s unsure how to explain them—we can summarize his presentation by saying that this body management technique relies on flexion and extension reflexes, which are automatic bodily responses designed to protect its integrity.
What Are Flexion and Extension Reflexes?
The flexion reflex is the one that contracts muscles to pull us away from a source of danger.
A common example is when you touch a hot surface with your hand; this reflex makes you pull your hand back quickly to avoid burns. To achieve this, the muscles contract instantly.
It’s worth noting that these automatic movements are much faster—up to 30 times faster—than movements we make consciously after thinking about them.
The extension reflex is the opposite of the flexion reflex. For example, when you’re engaged in an activity like walking and suddenly slip, your body reacts by extending your legs and arms to prevent a fall.
Both reflexes, flexion and extension, work automatically and quickly, leaving no time to think of an alternative.
In shibari, the Fuchin technique leverages these reflexes to manipulate the bound person’s body, using these automatic responses to manage movement.
The reflex itself lasts only a fraction of a second. You have to be very attentive. Identifying the precise moment is a skill that allows the person tying to guide the session smoothly, adjusting their timing and actions to the bound person’s reactions.
This isn’t a technique that’s applied in isolation, in any situation, or for any purpose. It needs to be integrated into the dynamics of the session in a way that doesn’t make it obvious you’re using it (urawaza).
That fluid and coordinated movement is the foundation of non-verbal communication. When you achieve it, you’ll begin to understand and speak the language of the body.
Criticism of This Explanation
First, we need to understand that Yagami Ren’s explanation comes from his experience and knowledge gained through practicing aikido. That’s why he proposes that odd exercise in the video.
And yes, it’s true that reflexes and certain “automatic movements” are resources used in this technique, but not in the way he describes. They don’t work like that.
These reactions are too fast for the person tying to use them to generate controlled movement.
As instructors committed to our students and to delivering accurate information in our classes, we always point out when such inaccuracies arise.
And this will happen more than once or twice, because, unfortunately, the “official” theory and techniques of Yagami Ryu have gaps and concepts that are not only outdated—as in the case of somebody techniques—but also, in certain areas like neurology and psychology, are outright incorrect and have been completely debunked by science.
At Shibari Dojo, we don’t base our training solely on our own knowledge. We also cross-reference it with professionals and researchers in each of the fields we cover.
This sometimes leads us to self-correct, continuously revise our methods, and even disagree with our own teacher.